7) Gypsum drilling fluid
Basic components: gypsum, SMC, SMP, SMT, FCLS, etc.
Features: By use of the common ion effect, add gypsum to inhibit the gypsum dissolution in formation.
8) MMH drilling fluid
Basic components: bentonite, mixed metal hydroxides (MMH), filtrate reducer and viscosity reducer
Features: MMH can provide a unique rheological property and owns the strong ability of inhibiting the formation hydration dispersion; meanwhile, use filtrate reducer, which does not destroy MMH-clay complex structure, to control filtrate loss.



9) Potassium-silicon-based drilling fluid
Basic components: KPAM, silicon stabilizer, silicon thinner, GKHm, SMP, and sulfonated asphalt products
Features: use silicon to stabilize shale and reduce the water wettability of formation, with a strong inhibitive ability, thermal stability and a strong ability of containing solids.
10) Polyalcohol or polyether drilling fluid
Basic components: polyalcohol or polyether treatment agent, anti-collapse agent, polymer, etc.
Features: the hydrophilicity of polyalcohol or polyether treatment agent is greatly affected by temperature. Below a certain temperature, the agent changes from water phase into oil phase, forms hydrophobic film on well wall, stabilizes well wall, inhibits hydration dispersion of cuttings and reduces the rig torque, and is harmless to environment.



11) Salt water drilling fluid
Basic components: inorganic salts, such as NaCl, salt-resistant viscosity reducer, filtrate reducer, salt inhibitor, etc.
Features: effectively inhibit osmotic hydration of shale, prevent formation collapse and control the influence of salt in formation on drilling fluid properties.
Typical formula: the salt water drilling fluid is basically similar to saturated salt water drilling fluid, but the dosages of treatment agents decrease along with the salt content decline in drilling fluid.
Applicable scope: pure salt-gypsum bed small in thickness and in shallow formation or middle-deep well section
12) Saturated salt water drilling fluid
Basic components: inorganic salts, such as NaCl, salt-resistant viscosity reducer, filtrate reducer, SMP products, sulfonated asphalt products, modified starch, salt inhibitor, etc.
Features: effectively inhibit hydration swelling of shale and dissolution of salt and gypsum, with a good lubricating property and thermal stability.
13) Water-in-oil emulsion drilling fluid
Basic components: diesel/mineral oil, organic soil, emulsifier, co-emulsifier, calcium chloride, water, etc.
Features: effectively inhibit salt dissolution and seal bedding fracture, prevent various complicated downhole conditions and accidents caused by borehole enlargement and borehole sloughing in salt-gypsum formation, and enhance well cementation quality.